And as the public swarmed into the cathedral’s still very new Open Treasure permanent display, the accents suggested they had come from far and wide.

One lady said she had come up from Hampshire on Saturday. “When I heard this was on, we came along straight away.”

There were voices from America, Ireland and all around the UK. They were young and old.

Probably they were in Durham for a range of reasons but the cathedral is a massive international draw and in this latest exhibition it can boast of something truly unique.

“This is the fourth rolling exhibition within Open Treasure since we opened its doors almost a year ago and a moment we have been looking forward to with great anticipation,” said Andrew Tremlett, Dean of Durham.

Marie-Thérèse Mayne, exhibitions officer and curator of Magna Carta & the Forest Charters, said: “There was a lot said about Magna Carta two years ago when it was the 800th anniversary of the document.

“This is the 800th anniversary of the Charter of the Forest which was first issued in 1217.

“We thought it was a marvellous opportunity to showcase Durham Cathedral’s collection because it’s unique.

“We have the only 1216 issue in existence and examples from 1225 and 1300.

“The document was reissued every few years because of modifications or maybe a change of king.”

That very first Magna Carta, sealed by King John at Runnymede against his will, was annulled on appeal to Pope Innocent III – causing uproar among the barons of the north who had grown sick of the king’s taxes.

After King John’s sudden death in October 1216, his nine-year-old son became Henry III but William Marshal, 1st Earl of Pembroke, became protector and regent.

He and papal legate (representative) Cardinal Guala Bicchieri moved quickly to secure the throne by offering the barons a new version of Magna Carta.

Their seals are missing but the 1216 Magna Carta is there in Open Treasure’s collections gallery where temperature and humidity are controlled.

Alongside it is the 1217 copy of the Charter of the Forest, the document which guaranteed access to land for commoners and protected them from harassment in royal forests.

The only other surviving example of this document is in Lincoln Cathedral.

Marie-Thérèse said Magna Carta, when first issued, was called the Charter of Liberties.

“The name was changed because of the Charter of the Forest being issued in 1217. It took out some of the clauses relating to the administration of royal forests and expanded on them.

“The original document was then renamed Magna Carta, the great charter, to differentiate it and from then on the documents were released alongside each other.”

Marie-Thérèse said copies of Magna Carta were distributed to cathedrals and county courts to be read aloud in public and absorbed by those who could understand Latin.

So why has Durham Cathedral got such a rich collection of these documents?

“Most people, when they got a new charter, disposed of the old one,” Marie-Thérèse said.

“The monks of Durham Cathedral kept them for future reference and also copied the text into books of charters called cartularies.”

You’ll see examples of these in the exhibition – while maybe offering thanks to the Durham monks for their hoarding instincts.

Marie-Thérèse said the collection survived the Dissolution of the Monasteries – ordered by Henry VIII after his break with Rome – because Durham’s monastery, whose rooms now accommodate Open Treasure, was connected to a cathedral and run under the auspices of the powerful Prince Bishops.

The Durham exhibition, said Marie-Thérèse, had been put together to show what the Magna Carta had meant for Durham and the North East.

“We look at the role of the Prince Bishops and the Church and the northern barons such as the Lord of Alnwick, Eustace de Vesci, and John Fitzherbert, Lord of Warkworth.

“The rebel barons came to be called the northerners.”

If in these ancient documents lie the seeds of our modern democracy, it seems they also speak of a centuries-old north/south divide.

Magna Carta & the Forest Charters, sponsored by law firm DAC Beachcroft and supported by Heritage Lottery Fund, runs at Durham Cathedral until September 9 – after which the precious documents will again disappear from public view.